1. Field of the Invention
The present invention generally relates to the field of firearms and, in particular, to firearms utilizing cartridges fed from a horizontal magazine and in which the cartridges are rotated 90.degree. after delivery from the magazine so that they can be presented properly to the barrel prior to discharge.
2. Description of Related Art
Ammunition magazines are well known in the prior art. The vast bulk of such magazines, however, discharge the cartridges in a plane that is parallel to the major flat surface of the magazine itself. A very small minority of magazines, however, discharge their cartridges at an angle perpendicular, i.e., 90.degree. to the major plane of the magazine. This is, of course, the case with most horizontal magazines. By "horizontal" the term is used to mean that the magazine lies in a plane parallel to that of the barrel. Since the use of horizontal magazines is relatively unique, the prior art related thereto is relatively limited
The following prior art magazine devices may be of possible relevance. U.S. Pat. No. 2,630,645 describes an abutment at the end of the magazine slide which holds laterally oriented cartridges in place. An expanding spring causes the abutment to cover the exit opening thereby preventing bullets from exiting the magazine.
U.S. Pat. No. 2,773,325 discloses a magazine wherein abutting shoulders limit the extent of insertion of the cartridge container.
U.S. Pat. No. 2,882,635 describes a cartridge container having an end cap which retains the cartridges within the container only until the container is loaded into a firearm and, thereafter, the cartridges are free to move to a transfer mechanism.
U.S. Pat. No. 2,448,081 describes another magazine which positions its cartridges laterally relative to the direction of fire and relies on an elevator to raise them to a transfer member which orients them with respect to the firing mechanism. Apparently, gravity retains them in the magazine well.
Finally, U.S. Pat. No. 4,286,499 describes a feed mechanism including a feed lip, and a bias spring, and a curved guide surface for guiding the cartridges downward to a transferring mechanism.
It is dear from a review of the patent prior art that mechanisms for keeping cartridges from falling out of horizontal magazines are an area of very limited development.
Similarly, devices which employ rotating transfer disks to deliver cartridges from a horizontal magazine to the barrel of an automatic or semi-automatic weapon are relatively limited in number. The following U.S. patents are believed to be typical of the state of the art.
U.S. Pat. No. 2,624,241 describes a transfer disk, including an arcuate slot which mates with a pin in the firearm's chamber to control rotation of a transfer disk.
U.S. Pat. No. 4,004,363 describes an arresting means for a rotatable cartridge chamber which also helps to limit travel. In that embodiment, a pin drops into a special detent to prevent further rotation.
U.S. Pat. No. 3,997,994 assigned to Heckler & Koch is of general interest in that it describes a swivel breech which is designed to accommodate variations in gas forces used to power the breech's swivel action so that the breech is limited to approximately 90.degree. of arcuate rotation without the need for a locking means as such. For similar mechanisms, also note the following U.S. Patents assigned to Heckler & Koch: U.S. Pat. Nos. 4,152,857 and 4,348,941.
Lastly, U.S. Pat. No. 5,610,362 is of general interest in that it discloses another mechanism for controlling the rotation of a rotatable cartridge transfer disk.
The improvements described in this disclosure relate primarily to mechanisms developed by the present inventors and described in U.S. Pat. No. 4,524,672 issued on Jun. 25, 1985 entitled "MAGAZINE AND FEED MECHANISM FOR FIREARMS" by Walter S. Balsavage, Jr. and U.S. Pat. No. 4,825,743 issued on May 2, 1989 entitled "MAGAZINE AND FEED MECHANISM FOR FIREARMS" naming Walter S. Balsavage and Floyd O. Aikman as co-inventors and assigned to Walter S. Balsavage, Jr., Trenton, N.J. The present invention is intended to improve over the specific mechanisms described in U.S. Pat. Nos. 4,524,672 and 4,825,743. While both devices perform well, two problems were noted. First, cartridges delivered from the horizontal magazine would sometimes fall out of the magazine or were not properly presented to the rotatable transfer disk by the insertion mechanism. Second, and synergistically, the rotatable transfer disk might occasionally travel beyond 90.degree. thereby misaligning the cartridge with the feed mechanism and causing a jam. This is more likely to happen with high-powered ammunition in which the momentum created by the recoil of the firearm was such that the transfer disk was overdriven beyond the 90.degree. alignment point. It has been found that by improving the magazine as described in this disclosure and improving the rotatable transfer disk so that it does not travel beyond 90.degree., synergistically enhances the performance and dependability of the firearm. Insofar as understood, none of the prior art references cited herein, or known to the inventors, hint, teach or disclose the inventive concept set forth herein.